Replaced back cover, now screen doesn't work

Hi,

I have an Iphone 3gs 32GB, and I replaced the original back cover which was covered in scratches, with a new back cover.

After I managed to get that done with one of the guides on this site, I found a new problem. The screen doesn't turn on anymore.

I know the phone is working fine and that it's on:

It vibrates and makes a sound and is sensed by the computer when I plug it in with my USB charger.

I think the problem might be that one of the cables for the screen could be damaged, specifically cable #1.

I made sure that everything was plugged in correctly, and nothing is solving my problem.

If cable #1 is indeed damaged, is there a way I can fix it myself inexpensively, What parts would I need?

Or do I need to replace the entire front panel?